The purpose of the present study was to evaluate the effects of continuously infused N-acetyl cysteine (NAC) on serum cytokine levels and gastric intramucosal pH in humans suffering from severe sepsis.

Fifty-three patients were included to the study. After applying 150 mg/kg NAC (n = 27, NAC group) bolus intravenously for 5 min, it was continued with 12.5 mg/kg/hour intravenously for 6 hours as an infusion. The control group (n = 26, control group) was administered the same dose of dextrose 5% solution. Hemodynamic parameters (heart rate, mean arterial pressure), nasopharyngeal body temperature, arterial blood gas changes, (pH, PO2, PCO2), plasma cytokin levels (IL-1β, IL2-R, IL-6, IL-8, tumor necrosis factor-α), biochemical parameters (hematocrit, leucocyte, thrombocyte, urea, creatinin, total billirubin, direct billirubin, total protein, albumin, serum glutamate oxalate transaminase, serum glutamate piruvate transaminase, sodium, potassium) and intramucosal pH, staying time in the intensive care unit, time of mechanical ventilation support, and mortality, with the control group, were recorded. All measurements were obtained at baseline (15 min before start of the study) and were repeated immediately after, and at 24 and 48 hours after NAC infusion. No differences were found according to these parameters.

We found that the effect of NAC infusion did not affect cytokine levels or patients' outcome or gastric intramucosal pH in severe sepsis in humans. Because of the limited number of patients in our study and the short period of observation, our findings need to be confirmed by larger clinical trials of NAC infused in a dose-titrated manner. However, our results do not support the use of NAC in patients with severe sepsis.